I wish that thunderbird would have worked for me when I had it on my machine. I really do.
I made sure that the settings were correct, but I could never get any outgoing messages to be sent. To bad for me, though.

No. It wasn't my firewall or AV either.

"God, from the mount Sinai
whose grey top shall tremble,
He descending, will Himself,
in thunder, lightning, and loud trumpet’s sound,
ordain them laws".

John Milton (1608-1674) in Paradise Lost

Ripley's SealLion's Believe it or Not! ~ NASCAR car crashes and Windows have just one thing in common.
Oh, oh. Better use LINUX.